Abstract

There is a saying: One man's meat is another man's poison. This will be recognized as a crude statement of the constitutional peculiarities and differences of various members of the human species, and is another indication of the penetrating insight of the folk-lore poet that precedes the slow march of science. Where science goes beyond the philosopher is in asking why and then proceeding to find the answer.

For the purposes of this study we may paraphrase the saying somewhat as follows: The more nearly two individuals resemble each other, the greater are their chances of developing the same disease.